Can't compile with Scala 2.13

Describe the bug Quarkus doesn’t work when Scala version is changed from 2.12 to 2.13.

Expected behavior Successfully compiled.

To Reproduce Steps to reproduce the behavior:

1. Open https://code.quarkus.io

2. Select Scala (I also selected Gradle, resteasy-jackson, jackson, jdbc-postgresql and mailer)

3. Download and extract the skeleton project

4. Update the Scala version in build.gradle to 2.13.1

5. In ExampleResource.scala, replace def hello() = "hello" with def hello() = List("hello").minOption.get – minOption is a new method in 2.13.

6. In the project’s working directory, ./gradlew quarkusDev

7. Notice the errors. You will get something like:

    > Task :compileScala                                                                                                                      
    [Error] C:\...\src\main\scala\...\ExampleResource.scala:11: value minOption is not a member of List[String]     
    one error found
   

Environment (please complete the following information):

• Output of uname -a or ver: Linux Ryzen5 4.4.0-18362-Microsoft #836-Microsoft Mon May 05 16:04:00 PST 2020 x86_64 x86_64 x86_64 GNU/Linux

• Output of java -version: openjdk version “11.0.3” 2019-04-16 OpenJDK Runtime Environment AdoptOpenJDK (build 11.0.3+7) OpenJDK 64-Bit Server VM AdoptOpenJDK (build 11.0.3+7, mixed mode)

• GraalVM version (if different from Java): N/A

• Quarkus version or git rev: 1.5.1.Final

• Build tool (ie. output of mvnw --version or gradlew --version): Gradle 6.3 Build time: 2020-03-24 19:52:07 UTC Revision: bacd40b727b0130eeac8855ae3f9fd9a0b207c60 Kotlin: 1.3.70 Groovy: 2.5.10 Ant: Apache Ant™ version 1.10.7 compiled on September 1 2019 JVM: 11.0.3 (AdoptOpenJDK 11.0.3+7) OS: Linux 4.4.0-18362-Microsoft amd64

[gsmet]

I created a draft PR here: https://github.com/quarkusio/quarkus/pull/25106 . I had to rework everything as my branch was really too old and too many things had changed. The good thing is that it was a lot simpler… except if I missed something 😃.

[gsmet]

I have a branch somewhere but it would need a refresh.